anchor folding spring dowel made of galvanized steel with half-ring tip for screwing in materials with empty space,

anchor automatic background ceiling chandelier construction cornice dowel drilling drywall empty fix fixing folding form galvanized gray grip halfring hole hollow hook iron isolated locking lying made materials mechanism metal mount nut plate reliable ring rod screw screwing shadow shelf space spring steel sticking support surface suspended thread tip unfold washer white wings woodfiber